title: Histopathologic response to highly purified liquid silicone injected intradermally in rats' skin.
abstract: BACKGROUND
  This study aimed to assess and compare the tissue response to small- and large-volume injections of pure liquid silicone in rats.
  
  
  METHODS
  The study used 25 Sprague-Dawley rats. Two different injection sites were determined for a single rat, and 5000 centistoke liquid silicone was injected subdermally using 0.2-0.3 ml (small volume) and 1 ml (large volume) injections. After the injections, 15 animals were killed at 4 weeks and 10 animals at 10 weeks. Tissue responses were evaluated under a light microscope.
  
  
  RESULTS
  At week 4, the numbers of lymphocytes and neutrophils were higher in the small-volume injection group. At week 10, the number of neutrophils decreased, and the numbers of macrophages and foreign body giant cells increased in the small-volume injection group, whereas the intensity and type of infiltrate in the large-volume injection group did not change significantly. The thickness of the fibrous capsule was greater in large-volume injection group at weeks 4 and 10. The thickness of the fibrous capsule did not change significantly in either group through time.
  
  
  CONCLUSIONS
  Purified high-density liquid injectable silicone causes a low-grade and well-tolerated inflammatory response during the long term and can be used when given as small-volume injections.
authors.affiliation: Department of Otorhinolaryngology, Acibadem University School of Medicine, Kadikoy, 34718 Istanbul, Turkey. ozcan.cakmak@gmail.com
authors.forename: Ozcan
authors.initials: O
authors.lastname: Cakmak
authors.forename: Huseyin Kemal
authors.initials: HK
authors.lastname: Turkoz
authors.forename: Senol
authors.initials: S
authors.lastname: Polat
authors.forename: Gediz Murat
authors.initials: GM
authors.lastname: Serin
authors.forename: Evren
authors.initials: E
authors.lastname: Hizal
authors.forename: Hasan
authors.initials: H
authors.lastname: Tanyeri
mesh_terms: D000818:Animals; D007271:Injections, Intradermal; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D012828:Silicones / Q000008:administration & dosage*; D012867:Skin / Q000187:drug effects / Q000473:pathology*
chemical_list: D012828:Silicones